Assemblies in accordance with the present invention can access a data storage medium having one or more disks. One such assembly comprises a mounting block including a bore and spacer, an arm stack connected with the top surface of the spacer, and a bottom arm connected with the bottom surface of the spacer. The arm stack comprises module(s) stacked on a top arm. The arm stack and bottom arm are designed such that either can be disconnected from the mounting block without disassembling the bore. By having a removably fastened arm stack and bottom arm, the assembly can be built at a relatively low cost without deformation. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.